A leatherback sea turtle hatchling makes its way to the sea (Image by Jual via Flickr)

A study published in the April 2012 issue of Ecological Applications uses satellite telemetry data to identify danger zones where sea turtles and fishing trawlers intersect at sea — with deadly consequences. The insights provided by the study will assist regulatory agencies determine limits to fishing, such as seasonal closures, to protect sea turtles, all seven species of which are considered endangered.

The researchers followed 135 females, some from the eastern Pacific and some from the western Pacific, over 15 years as they crisscrossed the ocean hunting for jellyfish. The study found that the migration patterns for the two Pacific populations were different. Western Pacific leatherbacks leave Indonesian nesting sites to feed in the South China Sea, Indonesian seas and southeastern Australia and along the U.S. West Coast, making them vulnerable to fishing nets in many different areas.

The eastern Pacific leatherbacks traveled from nesting sites in Mexico and Costa Rica to the southeastern Pacific, with many getting snagged in fishing gear along the coast of South America. Because the eastern population is more concentrated in range, its risk of extinction is greater, Bailey says.

The new findings could help decision makers plan short-term fishery closures. Bailey credits a recent decision to close a swordfish and thresher shark fishery in California from mid-August to mid-November each year with dramatically reducing leatherback bycatches. (In 2010 no turtles were caught.)

The speed with which acid levels have risen in the oceans has “caught scientists off-guard.” (Image by B Tal via Flickr)

The Christian Science Monitor reports that the speed with which acid levels have risen in the oceans has “caught scientists off-guard.” Ocean acidification was recently described by National Oceanic and Atmospheric Administration (NOAA) Administrator Jane Lubchenco as climate change’s “equally evil twin,” representing one of the biggest threats to life in the oceans. Lubchenco warned that acidification amounts to “osteoporosis of the sea” and threatens coral reefs, food security, and tourism around the world.

Scientists initially assumed that the carbon dioxide absorbed by the water would be sufficiently diluted as the oceans?mixed shallow and deeper waters. But most of the carbon dioxide and the subsequent chemical changes are being concentrated in surface waters, Lubchenco said.

“And those surface waters are changing much more rapidly than initial calculations have suggested,” she said. “It’s yet another reason to be very seriously concerned about the amount of carbon dioxide that is in the atmosphere now and the additional amount we continue to put out.”

Higher acidity levels are especially problematic for creatures such as oysters, because acid slows the growth of their shells. Experiments have shown other animals, such as clown fish, also suffer. In a study that mimicked the level of acidity scientists expect by the end of the century, clown fish began swimming toward predators, instead of away from them, because their sense of smell had been dulled.

In a study led by Lauren T. Toth at Florida Institute of Technology published in the journal, Science, coral reef ecosystems in the tropical eastern Pacific “collapsed for 2500 years, representing as much as 40% of their history, beginning about 4000 years ago.” A series of powerful El Nino events, which include periods of significantly warmer ocean temperature every three to seven years, coincided with the 2,500-year period of coral decline. This was followed by a cycle of La Nina events characterized by much cooler water, beginning 3,200 to 3,800 years ago. Corals recovered during the millenia since but now face a return to extreme weather conditions like those that wiped them out, due to climate change impacts. [Read more…]

The Journal Nature reports that, despite our best efforts to reduce fossil fuel emissions, sea level rise associated with climate change is unstoppable, even under the most aggressive actions on greenhouse gas mitigation. According to the study, the question now is not if sea level rise will continue but to what degree. And that’s the good news. Without concerted mitigation strategies, scientists predict that future sea level rise would be substantial and continue to rise for centuries to come.

Great Whales Near the Farallones, California Coast (Photo by Dan Shapiro, Courtesy of NOAA)

Whale populations, still recovering from centuries of hunting, continue to face a myriad of threats. But it’s often a surprise that one of the leading causes of death among whales around the globe is ship strikes. Now researchers are concerned that blue whales — the largest animals that have ever lived on the planet — are especially vulnerable to ship strikes in the Indian Ocean, according to the New York Times:

Leatherback Sea Turtle in the U.S. Virgin Islands (Image by USFWS/Southeast via Flickr)

Already the most critically endangered of all sea turtle species thanks to poaching and fishing impacts, new research led by Dr. Vincent Saba, a research fishery biologist with the NOAA National Marine Fisheries Service Northeast Fisheries Science Center, suggests that climate change could impede leatherback sea turtles’ ability to recover. [Read more…]

A new study in the journal Nature Climate Change shows that sea level along the U.S. Atlantic coast — one of the world’s most densely-populated coastal regions including New York, Boston and Norfolk, Virginia — is rising up to four times faster than the global average.

Sea level along the 620-mile coastline has risen by two to 3.7 millimeters per year since 1990. However, as temperatures continue to rise, sea level could rise well beyond the one-meter rise predicted by scientists, by up to an additional 30 centimeters within the next 90 years. In comparison, the average global sea level rise over the same period was between 0.6 and one millimeter per year. [Read more…]

Emperor penguins enter the water in Antarctica (Image by StormPetrel1 via Flickr)

ScienceDaily reports that a study led by researchers from the Woods Hole Oceanographic Institution, published in the June 20th, 2012 edition of the journal Global Change Biology, predicts that as global temperatures continue to rise, penguins in Terre Adelie, in East Antarctica, may eventually disappear. Emperor penguins are perhaps the best-known and most iconic of the Antarctic region and were featured in the popular film, March of the Penguins.

The BBC reports on research pointing to the importance of seagrasses to protecting coral reefs against the impacts of ocean acidification, caused by carbon dioxide from fossil fuel emissions dissolving in seawater, causing unprecedented increases in the ocean’s acidity.

Dr. Richard Unsworth of Swansea University, along with a team of scientists from Oxford University and James Cook University in Australia, found several types of seagrass which may reduce the acidity of water around reefs, protecting them from erosion from acidifying seas. [Read more…]